For many oilfield service operations, numerous chemicals must be used to achieve useful production from oil and gas wells, including surfactants, buffers, acids, bases, crosslinkers, breakers, etc. For most operations, chemicals are brought to the location in a concentrated form and diluted on site to achieve the desired final concentrations.
Typically, such liquid chemical concentrates are transported to the location of the well via trucks, trailers or skids, including stakebeds, float trailers, or liquid metering systems. Due to inaccurate measurement methods and other errors, it is often necessary to determine the amount of chemical in a given tank when the tank arrives. In part because the well is usually situated in a remote location, no sophisticated technique for measuring the quantity of chemical in the tank at the site of the well has been available. The measurement has traditionally required field personnel to climb above the tank and use a long measuring stick to determine the quantity of chemical in the tank.
Later, after some of the chemical in the tank has been discharged, it is often necessary or desirable to measure the amount of chemical remaining in the tank. As the instruments currently used for measuring the rate of discharge of the chemical from the tank are not sufficiently accurate, the tank is usually measured again by field personnel from above the tank.
The field personnel required to make these manual measurements are subjected to significant risks while performing the measurements. Many of the chemicals found in the tanks pose health risks, and because the field personnel are forced to work near openings in the tanks, they can be exposed to harmful chemicals. The field personnel also face the risk of falling, since manual measurements necessitate their climbing on top of the truck, trailer and/or tank.
In addition to the health and safety hazards attendant to the manual measuring method, using a measuring stick to determine the amount of chemical in the tank results in inherently inaccurate measurements. The measuring stick could be inserted at a slight angle and/or slight movements could cause the chemical to splash and produce an incorrect reading. Even under ideal conditions, a measuring stick can only be expected to determine the quantity of chemical remaining within a significant margin of error.
Traditional manual measurements require substantial time as well. Field personnel must then expend their valuable time by climbing on top of the tank, carefully measuring the depth of the chemical and climbing back down. The safety measures necessitated by the process consume additional time and human resources.
Due in part to these shortcomings of traditional chemical management, a weight-based system and method for measuring and managing dry chemical additives was developed and disclosed in U.S. Pat. Nos. 4,353,482, 4,410,106, 4,265,266, and 4,427,133. While these inventions present significant improvements over manual methods of measuring dry chemical additives, the accuracy of their measurements suffers due to failure to correct for off-axis forces, inclines, imprecise measurements of tank weight and other problems. In addition, a mobile weight-based management system for liquids, slurries, solutions or suspensions is desirable.
While embodiments of this disclosure have been depicted and described and are defined by reference to example embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.